#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#define LB32_MASK   0x00000001
#define LB64_MASK   0x0000000000000001
#define L64_MASK    0x00000000ffffffff
#define H64_MASK    0xffffffff00000000

/* Initial Permutation Table */
static char IP[] = {
    58, 50, 42, 34, 26, 18, 10,  2, 
    60, 52, 44, 36, 28, 20, 12,  4, 
    62, 54, 46, 38, 30, 22, 14,  6, 
    64, 56, 48, 40, 32, 24, 16,  8, 
    57, 49, 41, 33, 25, 17,  9,  1, 
    59, 51, 43, 35, 27, 19, 11,  3, 
    61, 53, 45, 37, 29, 21, 13,  5, 
    63, 55, 47, 39, 31, 23, 15,  7
};

/* Inverse Initial Permutation Table */
static char PI[] = {
    40,  8, 48, 16, 56, 24, 64, 32, 
    39,  7, 47, 15, 55, 23, 63, 31, 
    38,  6, 46, 14, 54, 22, 62, 30, 
    37,  5, 45, 13, 53, 21, 61, 29, 
    36,  4, 44, 12, 52, 20, 60, 28, 
    35,  3, 43, 11, 51, 19, 59, 27, 
    34,  2, 42, 10, 50, 18, 58, 26, 
    33,  1, 41,  9, 49, 17, 57, 25
};

/*Expansion table */
static char E[] = {
    32,  1,  2,  3,  4,  5,  
    4,  5,  6,  7,  8,  9,  
    8,  9, 10, 11, 12, 13, 
    12, 13, 14, 15, 16, 17, 
    16, 17, 18, 19, 20, 21, 
    20, 21, 22, 23, 24, 25, 
    24, 25, 26, 27, 28, 29, 
    28, 29, 30, 31, 32,  1
};

/* Post S-Box permutation */
static char P[] = {
    16,  7, 20, 21, 
    29, 12, 28, 17, 
    1, 15, 23, 26, 
    5, 18, 31, 10, 
    2,  8, 24, 14, 
    32, 27,  3,  9, 
    19, 13, 30,  6, 
    22, 11,  4, 25
};

/* The S-Box tables */
static char S[8][64] = {
    {
        /* S1 */
        14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7,  
        0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8,  
        4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0, 
        15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13
    },{
        /* S2 */
        15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10,  
        3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5,  
        0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15, 
        13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9
    },{
        /* S3 */
        10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8,  
        13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1,  
        13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7,
        1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12
    },{
        /* S4 */
        7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15,  
        13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9,  
        10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4,
        3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14
    },{
        /* S5 */
        2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9, 
        14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6, 
        4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14, 
        11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3
    },{
        /* S6 */
        12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11,
        10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8,
        9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6,
        4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13
    },{
        /* S7 */
        4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1,
        13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6,
        1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2,
        6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12
    },{
        /* S8 */
        13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7,
        1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2,
        7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8,
        2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11
    }
};

/* Permuted Choice 1 Table */
static char PC1[] = {
    57, 49, 41, 33, 25, 17,  9,
    1, 58, 50, 42, 34, 26, 18,
    10,  2, 59, 51, 43, 35, 27,
    19, 11,  3, 60, 52, 44, 36,

    63, 55, 47, 39, 31, 23, 15,
    7, 62, 54, 46, 38, 30, 22,
    14,  6, 61, 53, 45, 37, 29,
    21, 13,  5, 28, 20, 12,  4
};

/* Permuted Choice 2 Table */
static char PC2[] = {
    14, 17, 11, 24,  1,  5,
    3, 28, 15,  6, 21, 10,
    23, 19, 12,  4, 26,  8,
    16,  7, 27, 20, 13,  2,
    41, 52, 31, 37, 47, 55,
    30, 40, 51, 45, 33, 48,
    44, 49, 39, 56, 34, 53,
    46, 42, 50, 36, 29, 32
};

/* Iteration Shift Array */
static char iteration_shift[] = {
    /* 1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16 */
    1,  1,  2,  2,  2,  2,  2,  2,  1,  2,  2,  2,  2,  2,  2,  1
};

uint64_t des(uint64_t input, uint64_t key, char mode);
